This invention relates to improvements in the usage of the hopper and the hopper feed throat arrangement of plastic molding machines and particularly those machines of the injection type.
Relatively little effort has been expended by workers in this art to improving the feeding operations of the hoppers associated with plastic molding machines whether it has to do with the feed of the granular plastic material into the inlet of the machines or for cleaning the hoppers in preparation for receiving a new and different supply of plasticating material. In most if not all instances the hoppers were stationarily mounted on their respective plastic molding machines each having a valve controlled vent in the side wall of the hopper near the bottom thereof for the purpose of cleaning out the hopper. This usually required a man to mount the machine and scoop the reachable plastic pellets out of the hopper. This also required operating the machine to run out what plasticating material remained in the injection machine and resulting in an absolute waste of material. Lastly, the hopper was disconnected from the machine and placed over a collecting receptacle such as a barrel while the remnants of the plastic pellets were cleared out of the hopper, following which the hopper was remounted back on the machine. All this amounted to considerable machine down-time. In addition, the entry of metal particles into the molding machines caused not only serious damages to the machines but also longer machine down-time plus part cost and labor for the necessary repairs. In view of these difficulties and problems, it is apparent that there is a need for improvements in the art and especially in the direction of reducing machine down-time for cleaning the hoppers and for making repairs to the machine caused by the induction of foreign matter.